Actuators may be used to convert electronic signals into mechanical motion. In many applications, such as, for example, portable electronic devices, miniature cameras, optical telecommunications components, and medical instruments, it may be beneficial for miniature actuators to fit within the specific size, power, reliability, and cost constraints of the application.
MEMS is a miniaturization technology that uses processes such as photolithography and etching of silicon wafers to form highly precise mechanical structures with electronic functionality. MEMS actuators generally function in a similar fashion to conventional actuators but offer some beneficial features over conventional actuators, and are formed using MEMS processes.
In some applications, such as moving an image sensor in a camera for automatic focusing (AF) or optical image stabilization (OIS), an actuator may be used to move an optoelectronic device that has a number of electrical inputs and outputs. For example, European patent No. EP 0253375, entitled “Two-dimensional piezoelectric actuator,” by Fukada et al., teaches a design for a two-dimensional actuator that can be used to move an image sensor in a plane. The actuator taught by Fukada, however, is large and unamenable to space-constrained applications. For example, Fukuda' s actuator may be used in large, stand-alone digital cameras, but not in miniature cell phone cameras, due to the associated space constraints.
Unlike conventional piezoelectric actuators, MEMS actuators may be used to, for example, move or position certain passive components within miniature cell phone cameras. By way of example, U.S. Pat. No. 8,604,663, entitled “Motion controlled actuator,” by Roman Gutierrez et al., and U.S. Patent Application No. 2013/0077945 A1, entitled “Mems-based optical image stabilization,” by Xiaolei Liu et al., teach MEMS actuators for moving a lens in a miniature camera (e.g., for use in a cell phone).
Neither of these MEMS actuators is able to move an optoelectronic device that has a number of electrical inputs and outputs. In addition, both of these MEMS actuators utilize deployment mechanisms that add complexity, size, and cost. Furthermore, conventional MEMS actuators are limited in the number of electrical signals that may be routed thereto, typically due to the limited number of physical connections to the MEMS actuators. This limits the degree and type of movement that conventional MEMS actuators are able to achieve with respect to the passive components, and hence limits the overall effectiveness of conventional MEMS actuators.